QR

QR may refer to:

Arts and entertainment

 * Nippon Cultural Broadcasting (from call sign JOQR), a Tokyo radio station
 * Queen's Radio, a student radio station at Queen's University Belfast
 * Quiet Riot, an American rock band

Businesses

 * Qatar Airways (IATA code)
 * Queensland Rail, a company responsible for the railway system in Queensland, Australia
 * Quintana Roo (company), a triathlon-specific wetsuit and bicycle company

Places

 * Quintana Roo, a state of Mexico
 * Karakalpakstan (Qoraqalpog'iston Respublikasi), Uzbekistan (ISO 3166-2 subcode UZ-QR)

Science and technology

 * QR code (Quick Response code), a two-dimensional code
 * ATCvet code QR Respiratory system, a section of the Anatomical Therapeutic Chemical Classification System for veterinary medicinal products
 * DICOM Q/R, DICOM Query / Retrieve
 * Nissan QR engine
 * Quarter (unit)


 * qr.,, $1/4$ of a yard, equal to 9 inches
 * qr. av.,, $1/4$ of a hundredweight, equal to 2 stone or 28 pounds avoirdupois

Mathematics

 * QR decomposition, a decomposition of a matrix
 * QR algorithm, an eigenvalue algorithm to perform QR decomposition
 * Quadratic reciprocity, a theorem from modular arithmetic
 * Quasireversibility, a property of some queues
 * Reaction quotient (Qr), a function of the activities or concentrations of the chemical species involved in a chemical reaction

Other uses

 * Quarterly Review, a defunct literary and political periodical
 * Qatari riyal, the currency of Qatar